Delayed presentation of lower cervical facet dislocations: What to learn from past reports?

Delayed presentation of lower cervical facet dislocations is uncommon, and there is no standardized way to approach these neglected injuries. The literature on neglected lower cervical facet dislocations is limited to case reports and few retrospective studies. This justifies the need for a comprehensive review of this condition. Our purpose was to elaborate a review on the epidemiology, clinical and radiological presentation, and treatment techniques and approach to these neglected injuries. Middle-aged adults from 30 to 50 represent 73.8% of reported cases, and most of them are males (72.0%). The most affected level is C5–C6 (43.0%). While most delays are due to missed injuries (52.1%) and ineffective non-operative treatment (36.2%), the other reason for delay is negligence in seeking medical care (11.7%). Patients present with variable degrees of neurological deficit, persistent neck pain, and neck stiffness. Reported approaches and techniques to reduce and stabilize these injuries are highly variable and depend on the surgeon’s judgment, experience, and preference. Fibrotic tissues and bony fusion around the dislocated facet joint contribute to the reduction challenge, and 77.0% of closed reduction attempts fail. Anterior and posterior approaches to the cervical spine are used selectively or in combination for surgical release, reduction, and stabilization. Despite the lack of standardized treatment guidelines and different approaches, most of the authors reported improvement in pain, balance, and neurology post-surgery. Starting with the posterior surgical approach aims to achieve reduction compared to the anterior approach which largely aims at spinal decompression. Given the existing controversies, the need for quality prospective studies to determine the best treatment approach for lower cervical facet dislocations presenting with delay is evident.


Introduction
Lower cervical facet dislocations are unstable injuries that affect the anterior and posterior columns of the cervical spine [1].Allen-Ferguson classified lower cervical facet dislocations as flexion-distraction injuries, which are further subdivided into flexion sprain, unilateral facet dislocation, bilateral facet dislocation with up to 50% displacement (perched facets), and complete dislocation with >50% displacement [1,2].They are associated with variable degrees of spinal cord injury (SCI) [3,4].Lower cervical facet dislocations that present before 3 weeks are considered acute while those presenting after 3 weeks are considered old, chronic, or neglected [5][6][7].
While closed reduction for acute injuries is often successful, for lower cervical facet dislocations presenting with a delay beyond three weeks, fibrotic tissues and bony fusion around the injured facets and uncovertebral joints represent a challenge to reduction [7,8] (Figure 1).The reported success rate of closed reduction for acute injuries cannot be replicated to neglected cases [9,10].Neglected injuries require an adequate surgical release for reduction [11,12].There is no established standard treatment approach for neglected lower cervical facet dislocations owing to the rarity of cases and lack of quality studies to guide treatment decision-making.The literature on neglected lower cervical facet dislocations is limited to case reports and few retrospective studies.A comprehensive review of this condition is lacking.We reviewed 20 articles accounting for 165 patients with neglected lower cervical facet dislocations published in the English literature, and we elaborated a comprehensive synthesis of the epidemiology, clinical and radiological presentation, and variable treatment techniques and approaches to these neglected injuries.The overview of cases reported in the literature is portrayed in Table 1.
Other factors leading to the delayed presentation of lower cervical injuries include poverty, negligence, and the lack of resources (skilled surgeons, diagnostic and therapeutic infrastructures) [13].Among reported cases, 11.7% of patients with mild to moderate symptoms did not seek medical attention and consulted later when symptoms persisted or complications arose (Table 1).
Detailed history, including previous treatments, is the key to understanding the patient's complaints, general health status, and expectations.The examination of the neck checks for deformity and patient-controlled range of motion.The neurological examination evaluates sensory loss, muscle weakness, spasticity, hyperreflexia, abnormal plantar reflexes, and bowel/bladder function [13].Frankel grading [26] and ASIA impairment scale [27] are widely accepted to describe the neurological status.

Imaging
For neglected lower cervical facet dislocations, imaging is essential for diagnosis and surgical planning [12,15].The goal of imaging is to delineate the affected level, the alignment and stability, the extent of cord compression, eventual herniated disc fragments, and other changes related to trauma or degenerative process [8,11,12,15,28].Plain radiographs and computed tomography (CT) demonstrate variable degrees of anterolisthesis, sagittal malalignment, incongruent facet joint, and increased interspinous distance [29].These modalities help to rule out associated fractures of facets, endplates, lamina, or spinous processes that influence the planning in of terms approach, reduction, and fixation technique [30,31].Patientcontrolled dynamic views help to differentiate between stiff and flexible deformities [6].The CT scan provides a threedimensional pattern of the injury and delineates eventual bony fusion that requires surgical release before reduction [7, (Figure 2).The Magnetic Resonance Imaging (MRI) scan is the imaging of choice to assess the eventual disc herniation, spinal canal narrowing, spinal cord compressionand signal changes, and posterior ligamentous complex injury [13,15].CT myelogram is an alternative to MRI when the latter is contraindicated [3].

Treatment goals and expectations
The treatment for neglected lower cervical spine consists of delicate major surgical procedures, often in multiple stages [8,13,30,32].The core treatment objectives are the decompression of neural elements, restoring stability and alignment, and achieving solid fusion [8].Neck pain and malalignment significantly improve after successful surgical stabilization and fusion [5,7,14,22,33].Full recovery of SCI is possible but cannot be guaranteed as most of these injuries yield variable neurological outcomes post-surgery, with the majority improving by one or two Frankel grades [5,7,13,16].In addition, neurological deterioration is possible [17].Tables 1 and 2 portray the neurological outcome for reported cases.Complications and events to anticipate include bleeding, prolonged hospital stay, need for ICU admission, wound complications, pseudoarthrosis, and fixation failure (Table 3).When surgical risks outweigh the benefits, conservative treatment is preferred [11,34].
Despite the high failure rate, there was no neurological deterioration related to this procedure.Some authors avoided closed reduction attempts in cases with severe spinal canal narrowing or disc herniation [8,15].After successful closed reduction, most cases undergo anterior cervical discectomy and fusion [5,6,13,15,36].
The use of isolated posterior fixation, though uncommon, has been reported [5,6,23].In case of failure to achieve reduction, or when more stability is desired, the additional anterior procedure is warranted [6,14,17,22,25,37].After posterior wound closure, the patient is gently flipped in the supine position for the anterior surgery consisting of cervical discectomy to decompress neural tissues [12,14].Caspar distractor and interbody distractor are used to complete the reduction [7,41].Fluoroscopy images confirm the reduction before the final fixation with an interbody cage or iliac bone graft, supplemented by anterior plating [6,14,17,22,25,37].

Anterior (A) and Anterior-Posterior (A-P) surgical techniques
Lower cervical facet dislocations are associated with a high rate of intervertebral disc disruption and herniation [10].Though the posterior approach is preferred for irreducible facet dislocations, the anterior approach is ideal for decompression of neural tissues, especially in cases with disc herniation [8,12].After discectomy, caspar distractor, interbody distractor, or craniocervical traction help to obtain reduction which is confirmed with fluoroscopy before the final fixation with an interbody cage or iliac bone graft, supplemented by anterior plating [6][7][8]41].Anterior cervical corpectomy and strut cage fixation is another option for cases with fractured vertebral endplates and those with inaccessible disc fragments [28,30].
When anterior reduction maneuvers fail, or more stability is desired, the posterior approach is warranted for further release reduction and fixation with lateral mass screws or spinous process wiring [7] (Figure 4).
The need for more than two surgical procedures Due to the reduction challenges, neglected lower cervical facet dislocations often required three or four procedures.Anterior-Posterior-Anterior (A-P-A) [8,13,15,30], Posterior-Anterior-Posterior (P-A-P) [12,32], and Anterior-Posterior-Anterior-Posterior (A-P-A-P) [32] procedures are reported in the literature.For all these cases, the first or second procedures did not achieve reduction and it required further procedures.
Failure to reduce the dislocation with the anterior procedure warrants a posterior approach for further release and reduction [8,13,15,30].In this scenario, a temporary interbody spacer cage helps to maintain stability while proceeding with the posterior surgical release, reduction, and fixation [8].It requires a third anterior procedure to complete the anterior fixation and fusion [8,13,15,30].To avoid the third anterior procedure, surgeons tried different techniques [42][43][44].Ding et al. [7] secured the cancellous bone graft in the interbody space with a gelatin foam and longus colli muscles, and proceeded with posterior surgery to reduce and fix dislocated facets with lateral mass screws.
In the same line, for cases where it was not possible to get the reduction through the posterior approach, they proceeded with the anterior decompression and further release to achieve the reduction, and it required a third posterior procedure to complete the posterior fixation [12,32].
In general, anterior surgery for neglected lower cervical facet dislocations is aimed mainly at decompressing neural structures rather than reduction.For cases without disc herniation, authors advocated for starting with the posterior approach which, in most cases, achieved complete or near-complete reduction   L. Nkurikiyumukiza et al.: SICOT-J 2024, 10, 4 [5,13,14,32].The anterior approach is largely aimed at spinal decompression rather than reduction [8,12].These additional surgical procedures represent a burden and risk to patients, including but not limited to neurological deterioration, bleeding, radiation exposure, infection, airway complications, anesthesia complications, and cost.Longer operative time of more than 4 h and excessive blood loss were other drawbacks [8,12,13].

Conservative treatment, partial reduction, and in situ fusion
Lower cervical facet dislocations presenting with delay are sometimes found incidentally after an unrelated event.
Thompson and Hohl [11] treated conservatively an asymptomatic alcoholic patient with bilateral cervical facet dislocation who presented years after the index trauma.Shah et al. [34] reported 2 cases of neglected cervical facet dislocations that were managed conservatively.For all these cases, there was radiological fusion with moderate deformity, and without neurological deficit (Figure 5).
Conversely, corpectomy of the caudal vertebra and fusion in situ is an alternative technique for neglected lower cervical dislocations [16,33].It restored the alignment, and patients' neurology improved significantly (Figure 6).Even after both posterior and anterior release, failure to achieve reduction may necessitate recourse to in situ fixation and fusion [30].

Limitations
This review considered exclusively the English literature about neglected lower cervical facet dislocations that are mainly case reports and few retrospective studies.Being a narrative review, we cannot have a sound comparison of the techniques and approaches to these injuries.Most studies reported good outcomes and few postoperative complications.However, retrospective studies tend to underestimate spine surgery complications compared to prospective studies [45].While most of the reviewed publications involved the Asian population, the occurrence of neglected lower cervical facet dislocations in other low-and middle-income countries (LMICs) is underreported, and we could not address them in this review.

Conclusion
Delayed presentation of lower cervical facet dislocations remains a rare entity with notable controversies and variability around treatment techniques and approaches.Most patients are middle-aged adults, predominantly males.The most affected levels are C5-C6 and C6-C7.Delays are due to missed injuries, ineffective non-operative treatment, and negligence in seeking medical care.Patients present with variable degree of neurological deficits, persistent neck pain, and neck stiffness.Radiological assessment is important to delineate the injury morphology and changes related to the delay.Reduction of these injuries is challenging, and closed reduction is likely to fail.They required a variable combination of anterior and posterior surgical approaches for reduction and fixation.Reported approaches and techniques generally yielded improvement in pain, alignment, and neurology.The posterior approach aimed at surgical release and reduction while the anterior approach aimed at decompressing neural structures.Fusion in situ is an alternative to consider for failed reduction while conservative treatment may work for auto-fused cases.Given existing controversies, the need for quality prospective studies to determine the best treatment approach for lower cervical facet dislocations presenting with delay is evident.

Figure 5 .
Figure 5. Dynamic radiographs of the cervical spine showing neglected dislocation C5-C6 treated conservatively.Note the stability of the dislocated segment and anterior auto-fusion.

Table 1 .
Characteristics of published cases with neglected lower cervical facet dislocations.

Table 3 .
List of publications and approaches to neglected lower cervical facet dislocations.